Prior to the last patch, Bo literally had an answer for every single escape option out of his corner setups with the exception of breakers. B3 and F3 beautifully meaty delayed wakeups, meaty fart shut down tech rolls, great NJP and S4 to cover jump outs, and numerous 1 bar armor breaking setups.
Now that half the cast has double armor specials, armor breaking has become much more resource heavy and you won't always want to spend the resources to do it. However, he's not the only one here that has to deal with that. Still though, worth mentioning Bart could and still can break many armored or xray wakeups for 2 bars. Kitana, Goro, Scorpion, to name a few. Resource heavy or not, that's impressive lol.
On top of all that, every successful 50/50 from his setups nets him at least a healthy 28% into another setup of the same (or higher) caliber. Bo never really has to sacrifice much damage unless you live by the vortex, which still nets roughly about 20% per reset so it's not the worst. And when he fully cashes out of his setups? Say goodbye to half of that health bar no questions asked.
TL;DR - I'm not well-versed in some of these top 5 contender's corner games, so I can't say for certain that Bo should be up there, but IMO, he definitely should be in the discussion.